The goal of this clinical trial is to systematically compare the pain scores and anesthesia efficacy of IANB and MNB in the treatment of symptomatic mandibular first and second premolars. This study aims to address gaps in current evidence and clarify whether these anesthesia techniques differ in effectiveness and patient experience during endodontic procedures. The hypotheses include: (i) no difference in pain perception between IANB and MNB, (ii) no difference between first and second premolars with IANB, and (iii) no difference between first and second premolars with MNB.

Inclusion Criteria:

• Individuals classified as ASA 1 or ASA 2.
• Age range of 18 to 65 years.
• No known allergies to articaine or epinephrine.
• Absence of facial paresthesia.
• No use of analgesic medications within 6 hours prior to treatment.
• No use of medications, such as tricyclic antidepressants or beta blockers, that may interfere with anesthesia.
• No pathological conditions at the planned injection site.
• Periodontal pocket depth of 3 mm or less.
• Mandibular first or second premolars diagnosed with symptomatic irreversible pulpitis.
• Teeth meeting Glickman's gingival health criteria upon periodontal examination.
• Radiographically closed root apex with no detectable pathology.
• Patients must be literate and able to comprehend the use of a pain scale to provide informed consent voluntarily.

Exclusion Criteria:

• Presence of systemic conditions contraindicating endodontic treatment. Age below 18 or above 65 years.
• Pregnancy.
• Documented allergy to articaine with 1:100,000 epinephrine.
• Evidence of periapical pathology or radiolucency observed in radiographs.
• Recent use of central nervous system depressants or analgesic medication within 6 hours prior to treatment.
• Absence of reported lip numbness 10 minutes following IANB or MINB injection. Presence of a large restoration on the affected tooth.